The present invention relates to a vacuum coating installation as well as to a coupling device.
Installations of the first-mentioned type have been known for a long time, in which processing stations, which are grouped around a central distribution station, are operated from the central distribution station by way of a transporting arrangement or a robotic transportation system arranged in the distribution station and the distribution station is operated from the outside by way of an operating station, for example, by way of an inward and outward transfer station or one inward and one outward transfer station. with such installations, workpieces, such as storage disks, semiconductor wafers, are processed individually. Here, the material to be treated is formed by individual work pieces.
On the one hand, these installations permit relatively simple implementation of a desired process-related separation between the processing stations or between the distribution station and the processing stations or the operating station, as required for the very difficult processing on the above-mentioned workpieces. Furthermore, it is typical of such installations that the workpieces are essentially plane and flat, and must normally be processed, for example, coated, only on one side.
By way of these known installations highly difficult, complete layer systems can be implemented, which takes place continuously in a vacuum atmosphere and, as mentioned above, partially with a process-related separation of the individual processing steps.
Because of the high workpiece costs and the high processing costs, a relatively low throughput is accepted in the case of the above-mentioned installations as the result of the individual workpiece handling.
For the processing of workpieces which, with respect to the processing quality, for example, during their coating, are much less critical than the above-mentioned workpieces, thus, for example and particularly, for the application of wearing protection coating systems on tools, for example, for cutting, or on machine construction elements, less attention is paid to the frequency of occurring defective points, for example, with respect to the coating. A high throughput has priority. It is therefore customary to process such workpieces in vacuum coating installations in which a plurality of such workpieces are introduced as a batch and are, in each case, subjected to one processing step. If several vacuum processing steps are required, the batch is often transported as a whole from one installation to other installations and is subjected in-between to the ambient atmosphere.
In addition, the workpieces of the type addressed here, thus, for example, tool bodies of a highly complicated shape, for example, with spiral cutting edges, milling blades, etc., must be processed three-dimensionally. This takes place specifically and particularly also where the body shape is the most complex. It requires special additional measures, such as special movements of the workpiece bodies in the respective processing operation. In the case of large batch units, this significantly complicates the arrangement.
By way of such installations, it is therefore difficult to further reduce to a significant degree the overall manufacturing costs for the workpieces to be processed.
In the case of workpieces of the last-mentioned type, there is also the tendency to increase the quality demands with respect to the processing in many cases. For example, increased demands with respect to the operating efficiency of cutting tools or with respect to the stressing capacity of machine construction elements, in some cases, also result in a raised quality demand with respect to their processing. It is easily understood that the simultaneous meeting of possibly increased quality demands with respect to the processing and the primary throughput demands represent a challenge to the development.
Under a first aspect, the present invention has the object of suggesting an installation of the initially mentioned type in the case of which, while the advantages of individual-workpiece processing installations of the above-mentioned type are maintained, the high throughputs of batch processing installations are achieved andxe2x80x94if requiredxe2x80x94, the advantages with respect to the processing quality of the individual workpiece installations can also be implemented at reasonable cost. An installation is to be created which permits high throughputs, requires reasonable costs with respect to its construction and operation and in the case of which the processing is easily reproducible. In the above-mentioned sense, it should be possible to three-dimensionally treat and particularly coat highly complexly shaped workpiece bodies.
This object is achieved by a vacuum processing installation of the first-mentioned type which is characterized by providing the material to be treated is formed by individual workpiece holders of the installation, each having a plurality of workpiece supports, on at least one of the processing stations, a drive and a driving connection configured to be controllably established and released between drive and workpiece supports of a workpiece holder introduced in the processing station is provided for a three-dimensional workpiece processing in the processing station. Thus, no longer are individual workpieces used as the material to be treated but individual workpiece holders, each having a plurality of workpiece supports. In addition, the demanded three-dimensional processing, at least when coating, is implemented in that the workpieces are moved in and with their supports in at least one of the provided processing stations.
As a result, known single-process batch installations, according to the invention, now become processing stations at the installation according to the invention, in which case the transport from one batch installation to another no longer takes place via the ambient atmosphere but according to the invention by way of the distribution station which can be evacuated. Thus, the whole processing takes place in a vacuum. It is therefore also possible to separate the individual processing stations from one another to the required extent with respect to the process, thus the processing stations from the distribution station and therefore, if required, meet high quality demands.
However, primarily, the throughput with respect to the above-mentioned batch installations is not only maintained but even increased.
Furthermore, the installation according to the invention virtually always has at least one coating station.
Although this coating station can be constructed as a low-pressure CVD processing station, it is suggested, particularly with a view to a reasonable-cost application of wearing protection coating systems, that it have at least one plasma discharging distance as well as at least one inlet which is connected with a gas storage device with a reactive gas. In other words, preferably at least one of the stations is constructed as a PVD processing station or as a PECVD processing station.
In this case, for the simultaneous buildup of more complex layers or for the processing of the workpieces by two or more processes successively, several plasma discharging distances can definitely be provided in one processing station and, correspondingly, optionally several reactive gas inlets, if they do not interfere with the respective processing operations to be carried out sequentiallyxe2x80x94such as sputtering and etching.
For depositing wearing protection coating systems, preferably nitrogen and/or hydrogen and/or a carbon-containing gas and/or a silicon-containing gas is provided in the gas storage device.
If the processing station is constructed as a PVD processing station, it has at least one source which releases vapor particles into the environment. The vapor particles are released, for example, by sputtering from a solid-state target or by the thermal vaporizing from a molten mass or by a mixed form of these techniques, such as cathodic arc vaporizing. The released material is preferably a metal or a metal alloy, preferably containing Ti, W, Al and/or Cr or silicon, or an oxide, nitride, oxynitride, carbide, oxycarbide, oxycarbonitride of one of the above-mentioned metals/alloys. The above-mentioned metal compounds are reactively or non-reactively deposited. For the releasing of the solid-state coating components, the following sources are preferably used:
Vaporizing sources which use thermal vaporizing, as, for example, anodic arc vaporizing sources or electron beam vaporizing sources;
cathodic arc vaporizing sources;
sputtering sources, preferably magnetron sources.
Particularly for the depositing of wearing protection coating systems, it is further contemplated that another of the at least two provided processing stations be a heating station and/or an etching station.
If more than one processing step can be carried out at one and the same processing station, for example, heating as well as etching, a time control unit is preferably operatively connected with the station, which unit controls the sequence of the steps and their process parameters. This reduces the number of required transport steps and saves processing stations.
At the vacuum processing installation according to the invention, a time control unit is preferably provided which, on the one hand, is operatively connected with a drive for the transport arrangement in the distribution station for the material to be treated; on the other hand, the unit is operatively connected with the drive and/or the driving connection at at least one processing station; and controls the time sequence of transport cycles and processing cycles as well as operating cycles.
In another preferred embodiment, it is suggested that a sealing arrangement is provided on the transport arrangement for the material to be treated, which sealing arrangement can be operatively connected in a sealing manner with the openings and can be triggered optionally independently of the lifting movement of the transport arrangement for the material to be treated. This creates the possibility of possibly selectively, for example, in a transfer valve-type manner, close, in a process-related fashion, the opening between the operating station and the distribution station and/or the opening between a processing station and the distribution station, whether by establishing a pressure stage, for example, by a sealing gap; whether by establishing a complete vacuum separation by mutually contacting parts of the sealing arrangement on the transport arrangement and at the addressed opening.
In this case, it is definitely possible to optionally close certain openings in a manner which is not process-related during the operation of the assigned station with respect to the distribution station, such as a connection opening between the heating station and the distribution station, particularly if the additional processing stations can be pumped down separately and during whose operation the respective openings are closed in a process-related manner.
The process-related separating of the stations becomes particularly simple in that sealing elements are fixedly assigned to the workpiece holder or the workpiece holders for workpieces which require such a separation, which sealing elements, forming a unit with the holder, move through the installation.
As initially mentioned, it is often very important to three-dimensionally process without gaps, particularly to coat, three-dimensionally highly complexly shaped workpiece bodies. This is achieved in that, between the workpieces and particularly directed sources, for example, at a processing station for etching or sputter coating, a relative movement is established. For this purpose, it is suggested to provide a driving connection, which finally acts upon the workpiece supports, between a drive and a respective workpiece holder. If, between the station-side stationary source and the workpiece holder, a relative movement is established, particularly preferably a rotational movement, thus ensures an often already sufficient three-dimensional processing. However, in a preferred embodiment, the above-mentioned driving connection is additionally established on workpiece supports which are movably disposed on the workpiece holder, whereby, as particularly by way of a planetary transmission, on the one hand, the workpiece holder and, thereon, on the other hand, the workpiece supports, are caused to carry out a rotational movement, in particular.
Furthermore, for the whole installation, a central control unit is preferably provided which is preferably freely programmable, that is, has optionally retrievable, freely programmed and stored sequences. On the one hand, this control unit pulses the operation of the transport arrangement; on the other hand, it pulses the drive and/or the driving connection at the at least one processing station as well as the operation of valves, thus, for example, transfer valves at the operating station to the distribution station, and, in addition, the process operation of the stations.
When transporting workpiece holders of the initially mentioned type from one station to the other, it is necessary to establish a coupling between the respective stations and the respective workpiece holder; whether this is an electric coupling, for example, for the biassing of the workpieces, or a mechanically coupling, finally, for the rotational drive of the workpieces. Other couplings may also be desirable, as, for example, for a cooling medium which is introduced into the workpiece holders. In order to implement such a coupling, a processing station truncated-cone wheel is provided at the installation of the first-mentioned type on at least one of the processing stations, as well as, at the workpiece holders, a projecting workpiece holder truncated-cone wheel is provided, the facesxe2x80x94preferably at last one of the smaller facesxe2x80x94on the one hand, of the processing station truncated-cone wheel and, in each case, of a workpiece holder truncated-cone wheel resting on one another when the workpiece holder is in the processing position in the processing station. Preferably at least one of the truncated-cone wheels is disposed in an axially resilient manner, whereby, when the workpiece holder with its wheel, preferably in a flat, particularly linear movement, is introduced into the station, the truncated-cone wheels first contact one another along their surface areas and, because of the wedge-effect of the mutually abutting cone envelope surfaces come to rest upon one another, as mentioned above, stressed against the spring force.
In a preferred embodiment, the workpiece-side truncated-cone wheel can be coupled with workpiece supports at the workpiece holder rotary drive, and a motor-operated rotary drive is then provided on the station side, which rotary drive, in the processing position of the workpiece holder, is coupled with the workpiece-holder-side truncated-cone wheel.
The station-side rotary drive, finally, for the workpiece supports on the workpiece holder, preferably operates by way of the station-side truncated-cone wheel onto the workpiece-holder-side truncated-cone wheel, or acts, by way of a drive operating independently of the station-side truncated-cone wheel, onto the workpiece-holder-side truncated-cone wheel.
In a further preferred embodiment of the installation according to the inventionxe2x80x94in which the mentioned wheels are not or not only used for the drive transmissionxe2x80x94, the station-side truncated-cone wheel as well as the workpiece-holder-side truncated-cone wheel is constructed in an electrically conductive manner at least on the truncated cone facesxe2x80x94in this case, at least on one of the smaller facesxe2x80x94, and the electrically conductive surface of the workpiece-holder-side truncated-cone wheel is connected in an electrically conductive manner with workpiece supports, whereas the electrically conductive small face of the station-side truncated-cone wheel is connected with a preferably adjustable electric source. This permits the establishing of a mechanical drive coupling and/or of an electric connection coupling between respective stations and work-piece holders by the provided truncated-cone wheels.
Although, as mentioned, the above-mentioned coupling forms a preferred embodiment of the initially mentioned installation, it is suggested to use the electric and/or mechanical coupling arrangement always between a vacuum processing station and a workpiece holder with workpieces to be processed in the station, that is, also for single-station installations in that a station-side truncated-cone wheel and a workpiece-holder-side truncated-cone wheel are provided whose facesxe2x80x94in this case, preferably comprising at least one of the smaller facesxe2x80x94rest on one another in the processing position of the workpiece holder in the station and thus establish a mechanical drive connection and/or an electric transmission connection from the station to the workpiece holder.
Furthermore, in a preferred embodiment of the initially first-mentioned processing installation, one shears-type mechanism respectively is provided on the transport arrangement for the material to be treated, in the distribution station, for individual workpiece holders, having a pair of lever arrangements which are centrally swivellably disposed relative to one another such that the lever arms have the same length from the swivel bearing to the respective lever end bearings. In a further preferred embodiment, at least one of the end-disposed lever swivel bearings of the shears-type mechanism is linearly displaceably disposed on a central part of the transport arrangement centrally provided in the distribution station, the shears-type mechanism drive comprising a linear drive for the at least one linearly movably disposed end bearing of the shears-type mechanism or a non-linear drive which preferably acts by way of a cam plate with transmission levers upon one of the shears-type mechanism levers.
If, at the initially first-mentioned processing installations, stations are to be separated with respect to the process, between which relatively large pressure differences exist, preferably starting at 4 mbar, the process-related separation by the above-mentioned sealing plate is preferably additionally secured by a tensioning device which can be operated independently of the transport arrangement. Preferably, this tensioning device has a roller arrangement which can be displaced by a motor, on the station side or the sealing plate side, as well as a cam plate, correspondingly on the sealing plate side or the station side, the roller arrangement being in an operative connection with the curved path the cam plate, for establishing or releasing a sealing pressure between the sealing plate and the opening edge.
Although this above-mentioned additional sealing protection is preferably also used on the initially mentioned, first-mentioned installation, it can naturally also be used on installations in which, for example, only one processing station is provided, as, for example, in the case of transfer stations. Basically, according to the invention, a vacuum processing installation is obtained which has at least one opening of the through-transport or for the processing of workpieces, in the case of which, with respect to the opening, a driven movable sealing plate is provided as well as a tensioning device which is mounted in the area of the opening and has a motor drive for establishing a defined sealing pressure between the sealing plate and the opening edge.